Recently, digital TV services using a wired or wireless communication network are widely spread. The digital TV services may provide various services that typical analog broadcasting services cannot provide.
For example, in the case of Internet Protocol Television (IPTV) service, i.e. one type of the digital TV services, it provides interactive contents to allow a user actively select the type and viewing time of a program. The IPTV service may provide various additional services such as internet search, home shopping, and online gaming, on the basis of such an interactivity.